Sweetie has had a blister on her vulva for about two weeks now – or at least it started as a blister but now looks more like an open sore. Some days it looks red and inflamed and other days it looks pink and calmer. Other than this, and a small patch of dry skin, her bottom is fine.

I'm letting her go bare-bottomed all the time she's at home, and I know they're slathering on the Sudocreme at nursery. Should it be taking this long to heal, and is there anything else I can do? Nappies are washed at 40º bio with the occasional 60º non-bio wash.

Sudocreme shouldn't be slathered on - it blocks the nappies, and also blocks air to the skin, should be put on as a very thin layer only Put on thickly it can stop the skin from healing... Might be worth trying a different cream - a lot of people like metanium I think when nothing else works, don't think you need much either but it can stain nappies I think... Never used it tho' but I'm sure someone else will advise...

Might be worth keeping a food diary to see which days it's worse and better as it could be something she's eating is coming through in her wee/poo and aggravating it...

Overall answer is no it should not be taking this long to heal.

Also I would wash at 60 in bio while you've got a rash and once she's all healed you can go back to 40...

This morning it looked like there was another blister developing, so I'm going to phone the health visitor today and maybe take her to the clinic tomorrow.

One worry I have is that I recently bought some second-hand nappies, and I know that the seller was having problems with nappy rash with these nappies in particular, so now I'm wondering if there's some sort of infectious agent in the nappy somehow. I don't want to stop using them if I can help it, but would it be worth swapping to sposies for a few days to see if it clears up a bit?

Well, the health visitor said it was fine and just to carry on doing what I've been doing, perhaps with Metanium. But, despite Metanium, it's getting worse – the open sore is, if anything, larger, and now there's a big red patch around it and over to the other side of the vulva too. The red patch grew particularly after one night when she took ages to go sleep in the evening and I knew she'd peed in her nappy but couldn't change it because I'd just done a wash and nothing else was dry! So she sat in it all night, which can't have helped.

It's obviously bothering her: she points at it and says 'Ow', and then asks for 'moin-mun' (ointment). This morning she pointed at the Metanium from her cot as soon as I got into the room, and said 'Pappy' (nappy), so I got her up and sorted her bottom out. Then she brought me the Calpol!